1. Field of the Invention
This invention relates generally to enhanced lane tracking capability of an automobile and, more particularly, to a method for selecting an anchor lane using navigation and digital map information, leading vehicle trajectories, and other data, to improve lane tracking performance at lane merge and split locations.
2. Discussion of the Related Art
Vehicle lane tracking systems usually employ cameras and image processing technology for identifying lane boundary lines marked on a road. Lane tracking systems may also use other technologies, such as data from magnetic lane boundary markers embedded in specially-prepared roads. Regardless of the type of data used to detect lane boundaries, typical lane tracking systems are designed to position a vehicle in the center of a lane which is assumed to have parallel left and right boundaries.
In situations where the left and right boundaries of a lane are not parallel—such as where an entrance ramp merges with a through lane, or where an exit lane splits from a through lane—typical lane tracking systems may not exhibit the desired behavior. For example, where an exit lane splits from a through lane, and the distance between the left and right lane boundaries is increasing, a typical lane tracking system may keep the vehicle centered between the diverging left and right boundary for a period of time. The system will ultimately have to select either the through lane or the exit lane for tracking, and this selection will cause a sudden, unwanted lateral maneuver of the vehicle. Furthermore, typical lane tracking systems may have difficulty dealing with the ambiguity caused by missing or obscured lane markers.
A lane tracking system is needed which uses all available data to select an anchor lane and exhibits improved lane tracking performance in lane merge and exit scenarios.